Data published in The Lancet over the weekend lent further support to Johnson & Johnson’s hope of developing the first treatment option for premature ejaculation, a condition thought to be more common that erectile dysfunction.
The publication of the data, which prompted wide coverage in the press, comes just months after the US Food and Drug Administration turned down J&J’s application to market dapoxetine for premature application.
The data on dapoxetine, first reported in May 2005, show that the drug was able to triple the duration of intercourse in men who had been with the same partner for at least six months and persistently suffered from premature ejaculation. It was also effective in extending intercourse in men with the worst symptoms, those who ejaculated within seconds of penetration.
The study, by researchers from the University of Minnesota in the USA, enrolled 2,614 men and who received either placebo or a low or high dose of dapoxetine, taken one to three hours before sex.
At the start of the 12-week trial, the men ejaculated on average less than a minute after penetration. By the end, those taking the lower 30mg dose were lasting 2.78 minutes, while those on the higher 60mg dose managed 3.32 minutes. Those in the placebo group lasted an average of 1.75 minutes by the end of the study.
For comparison, a recent study published in the Journal of Sexual Medicine found that the average duration of intercourse for a normal man is around seven minutes.
"On-demand dapoxetine is an effective and generally well tolerated treatment for men with moderate-to-severe premature ejaculation," said Dr Jon Pryor of the University of Minnesota, who led the study
If it reaches the market, dapoxetine would be the first treatment option for patients developed specifically for premature ejaculation, which at present is managed using behavioural therapy or older, 'off-label' drugs, mainly antidepressants.
Dapoxetine is a selective serotonin reuptake inhibitor, in the same class as many of the antidepressants used to treat premature ejaculation at the moment, but is the only one to have been studied this extensively in clinical trials. Side effects from the treatment included nausea, headache and upset stomach.
Critics claim that other SSRIs have been shown to be more effective in treating the condition, and that while premature ejaculation is claimed to affect around a quarter of men at some point, less than 5% suffer from it chronically. It is only the latter group that should be treated with drugs, they suggest, as premature ejaculation in most men is part of the normal spectrum of sexual performance.
The drug has not been submitted in Europe, as J&J is mindful of the difficulties faced by Pfizer when it first tried to persuade health systems to reimburse its erectile dysfunction treatment Viagra (sildenafil).